This is a North Face backpack that my husband used. It's 25 liters. It looks relatively clean to the untrained eye, but the logo on the shoulder straps is slightly faded, so I've marked it as having some scratches and dirt. As you can see in the sixth photo, the back has a metal frame that curves it, and the part that touches your back is mesh, so it seems to be well-ventilated and good for summer. However, because of the curve, it doesn't give the impression that it can hold a lot of stuff. But that's just the way the product is, so please understand.